Fluid operated pump with separate engine valve



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Aug. 23, 1960 c. J. COBERLY FLUID OPERATED PUMP WITH SEPARATE ENGINE VALVE Filed July 19, 1956 11 Sheets-shewI 3 (ZAQENCE 6].' bes/any,

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Aug. 23, 1960 c. coBERLY PLUIE OPERATED PUMP WITH SEPARATE ENGINE VALVE Filed July 19, 1956 l1 Sheets-Sheet 10 CLARE/VCE Cl' (26521.54 m4/Evra?.

Aug. 23, 1960 c. .1. coBERLY FLUID OPERATED PUMP WITH SEPARATE ENGINE VALVE Filed July 19, 1956 11 sheets-sheet 11v United States FLUID OPERATED PUMP WITH SEPARATE ENGINE VALVE The present invention relates in general to fluid operated pumps and pumping systems for wells, and particularly oil Wells, and a general object of the invention is to provide improved equipment of this character.

Basically, a fluid operated oil well pump of the reciprocating type includes interconnected engine and pump piston means and includes engine valve means for alternately applying high and low pressures to opposed faces of the engine piston means so as to reciprocate the two piston means, whereby the pump piston means pumps fluid from the well upwardly through a production tubing to the surface. The operating iiuid for actuating the pump, which is usually clean crude oil, is conveyed downwardly thereto at a relatively high pressure through a supply tubing set in the well, the spent operating lluid discharged by the pump at a lower pressure either being mixed with the production uid and being returned to the surface through the production tubing, or being returned to the surface through a separte, return tubing set in the Well. The iluid operated pump may be of the single acting type, or the double acting type, and various features of the present invention may be embodied in a pump of either type, although the single acting type will be considered primarily hereinafter as a matter of convenience. Fluid operated pumps are also either of the free type, or the set type, a pump of the former type being movable between its operating position in the well and the surface through the tubing system associated therewith so that removal of the tubing system in order to remove the pump is unnecessary. With a pump of the sert type, on the other hand, removal of at least part of the tubing system is necessary to permit removal of the pump since the pump is attached to one of the tubes of the system. Various features of the present invention are applicable to pumps of either of these types, although pumping equipment of the free type will be considered primarily hereinafter, the invention -being particularly applicable to this type.

Since the operating fluid for a iluid operated pump is delivered thereto from the surface and since the production fluid pumped thereby is delivered to the pump from therebeneath, it is conventional to locate the engine means of the pump, including the engine piston means and the engine valve means, in the upper end of the pump unit and to locate the pump means in the lower end thereof. Also, locating the pump means in the lower end of the unit is necessary in a well where the fluid level is very low in order to permit pumping the Well to its full capacity. In a conventional tluid operated pump of this nature, the engine means is located at the upper end of the unit in axial alignment With the pump means. With this conventional construction, it is necessary to provide a by-pass around the engine for the production uid, irrespective of whether the production uid is conveyed to the surface through a production tubing in alignment with the pump, or through a production tubing spaced laterally from the axis of the pump. While such bypassing of the production ow around the engine can be atent Vce accomplished satisfactorily, my Patent No. 2,589,671, issued March 18, 1952, and my co-pending application Serial No. 487,303, tiled February l0, 1955, now Patent No. 2,869,470 illustrating how the production ow may be by-passed around the engine into a production tubing in axial alignment with the pump, such by-passing of the production iiuid nevertheless imposes problems and one primary object of the present invention is to provide a fluid operated pump wherein such problems are overcome by flowing the production fluid axially through a pump unit and directly into a production tubing in axial alignment with such unit.

Considering another phase of the invention, the engine valve or engine valve means of a fluid operated pump is the most critical component thereof from the standpoint of maintenance, the cost of repairing a fluid operated pump and the frequency with which repairs are necessaryk being determined primarily by the engine valve. It is probably safe to say that under average conditions, a fluid operated pump would be capable of operating twice as long without removal from the well for repairs if the service life of the engine valve could be made equal to that of the remainder of the pump. However, this is impossible to attain with engine valve materials presently available. In other words, there are no engine valve materials available at the present time which will withstand both corrosion and abrasion at the high pressures and high temperatures existing in fluid operated well pumping systems, to an extent suicient to attain an engine valve service life anywhere near the service life of the remainder of the pump. Another primary object of the invention is to overcome the foregoing problems by making the engine valve a separate valve unit which may be removed from the well for service or repair independently of the remaining components of the pump, such remaining components being referred to hereinafter as constituting a pump unit.

Another problem which is encountered in connection with conventional uid operated pumps of the free type is that removal of such pumps hydraulically sometimes results in intermingling of the operating Huid with the production uid, the latter frequently containing such foreign matter .as water and sand, yand results in loosening products of corrosion which may line the interior of the pump tubing, i.e., the tubing through which the free pump is circulated between the surface and its operating position in the well. When `such :a conventional fluid operated pump is reinstalled, yor a replacement pump is installed, the pump is exposed to much of this foreign material and at least `some of it passes through the pump when it is first started, -thereby causing excessive wear. Also, the pump m-ay not start at all under such conditions and may have to be removed again for cleaning, and possibly further repair. In `any event, the first few strokes of the pump may cause las much wear and damage, particularly to the engine valve, :as months of normal operation. Still another primary object of the invention is .to overcome such problems by making the engine valve a separate valve unit which is installed, operated and removed in the clean operating lluid system only so `that it is impossible for foreign matter to enter the valve unit from the sources mentioned.

With the lforegoing general discussion and primary objects of the invention as background, various more specific objects of the invention and various advantages yof and new results attainable with the invention will now be considered.

including interconnected engine and pump piston means and the valve unit including engine valve means for applying operating fluid pressure to the engine piston means to reciprocate the engine and pump piston means.

Another important object of the invention is to provide a fluid operated pump having separate pump and valve units wherein the valve unit is spaced laterally from and located alongside of the pump unit and wherein production lluid flow takes place through the pump unit axially thereof.

Another object is to provide la fluid operated pump having separate pump and valve units wherein the valve unit is of the free type so that it may be installed in and removed from the well Lreadily 4without disturbing the tubing system.

Still another object is to provide la fluid operated pump having separate pump and valve units wherein both units are of the free type to provide for installation and removal thereof without disturbing the tubing system.

A further object is to provide a fluid operated pump including separate, free pump and valve units movable into and out of Ithe well independently of each other or simultaneously.

Another object is to provide a free pump wherein separate valve and pump units are movable into and out of the Well hydraulically through different tubings of the tubing system.

Another object is to provide a fluid operated pumping system wherein a lfree pump unit is movable between Ithe surface and its operating position in the well hydraulically through a pump tubing which also serves as the production tubing, and wherein a separate free valve unit for controlling the operation of the pump unit is movable hydraulically between the surface and its operating position in Jthe Well through a valve tubing, which is preferably the supply tubing for delivering operating fluid under pressure to the pump.

By circulating the pump unit into and out of the well through the production tubing and by circulating the valve unit into and out of the well through the supply tubing, .the valve unit may be removed and/or installed without exposure to foreign matter tending to produce excessive wear, and the pump unit may be installed and/or removed without exposing the valve unit to materials likely to damage it or cause excessive wear thereof. Thus, the present invention eliminates a great deal o-f engine valve trouble, which is an important feature of the invention.

Not only does the present invention permit separate removal of the engine valve and prevent exposure of the engine valve to foreign matter by making the engine valve ya separate unit exposed only 4to the clean operating fluid system, but it attains various other advantages as well. For example, the invention results in a small valve unit which may be removed from the well hydraulically with a relatively small volume of operating uid at a relatively low pressure as compared to the volume .and pressure required to remove the entire pump from the well. Consequently, surface pumping equipment capable of removing the entire pump in one hour has suliicient capacity to remove the valve unit in ten minutes, or less. Also, since the valve unit is small and light, it may be displaced to the surface hydraulically without the use of any packer cups thereon to prevent or reduce fluid by-pass. As `an example, a valve unit of the present invention for use with a 11A inch pump unit may be only 5A; inch in diameter and l2 inches long -and may weigh approximately l5 ounces. The hydraulic pressure required to balance this weight is only 3 p.s.i.

In addition to the other advantages mentioned, such Ia small valve unit has the advantage of enabling a pumper to carry enough of them in his .automobile to service a large number of wells. Further, since engine valves for fluid operated pumps are precision devices which can be repaired properly only by skilled mechanics in shops provided with precision equipment, the separate valve units of the present invention, being small and light, may be flown great .distances to .a properly equipped shop at mall cost. Thus, one properly equipped plant can service valve units of the present invention from every oil field in an extremely large area without excessive delay and at a lower net cost since the savings attainable as the result of a large operation more than olset the shipping costs, even by air.

Another important advantage of the present invention resulting from locating the engine valve means out of axial alignment with the engine and pump piston means, preferably in theV form of a separate valve unit alongside of a pump unit incorporating the engine and pump piston means, is that the production fluid pumped by the pump piston means may llow axially through the engine and pump piston means from a production lluid inlet at the lower end of the pump unit to a production fluid outlet at the upper end thereof. The pump unit is preferably axially aligned with the production tubing, and is preferably hydraulically movable therethrough between its operating position and the surface, so that the `axial production fluid flow through the pump unit discharges axially into the production tubing. Thus, straight-line production fluid llow through the pump unit into the production tubing is attained Without any necessity for laterally by-passing the engine, which is an important feature.

An important object of the invention is to provide a iluid operated pump in which the engine or engine means is concentric with and surrounds a reduced section of a single plunger which constitutes both an engine piston means and a pump piston means.

More particularly, an object of the invention is to provide a combined engine and pump piston means incorporated in a single plunger having intermediate its ends a section of reduced diameter to provide two transverse annular areas which face each other and which erve as engine areas.

Another object is to provide a fluid operated pump which includes engine valve means alongside and spaced laterally from the plunger described in the preceding paragraph for alternately applying the operating fluid pressure and the spent operating fluid pressure to at least one of the transverse engine areas to produce reciprocatory movement of the plunger.

Another object is to provide a single acting, fluid operated pump the return stroke of which is produced by applying either the operating fluid pressure or the spent operating lluid pressure to two oppositely facing, transverse surfaces of slightly different areas, such as slightly different engine areas formed at the ends of the reduced intermediate section of the combined engine and pump plunger mentioned.

Another object is to -provide a single acting, fluid operated pump wherein the working stroke is produced by applying the operating lluid pressure and the spent operating fluid pressure to oppositely facing, transverse areas, these areas being slightly different to produce the return stroke upon application of the same prmsure to both.

Another object is to provide a single acting, fluid operated pump which includes a plunger 'movable upwardly during its working stroke and carrying a Working valve, and which includes a standing valve below the plunger. Another object in this connection is to provide two standing valves, one below the plunger and one above the plunger.

Another object of the invention is to provide a single acting, fluid operated pump having engine valve means which includes governing means for throttling the flow of operating lluid under pressure to prevent racing of the plunger during its working stroke when the load thereon is less than apredetermined value.

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Another object is to provide a single acting, uid operated pump having a plunger with an upward working stroke and having a standing valve above the plunger and to provide such a pump with an engine valve means havin ggoverning means for controlling the plunger speed during its working stroke.

A further object is to provide a single acting, fluid operated pump having a plunger which moves downwardly during its return stroke and having a standing valve below the plunger, and to provide such a pump with an engine valve means including governing means for controlling the piston speed during the return stroke.

Another object is to provide a free valve unit for use with a separate pump unit and having a three-speed action.

Still another object is to provide a Ifree valve unit having a governing action.

Another object is to provide a free valve unit for use with a separate pump unit and having governing means for controlling the speed of a plunger in the pump unit with a throttling action.

Still another object is to provide a free valve unit for use with a separate pump unit which governs by throttling the operating fluid ow to a plunger in the pump unit, or the spent operating fluid flow therefrom, whenever there is less than a predetermined load on the plunger during the working stroke thereof.

Still another object is to provide a free valve unit which `operates with a governing action during either or both strokes of a plunger controlled thereby.

[Another object of the invention is to provide a pump unit for insertion into a pump chamber wherein the pump unit has a production fluid outlet at the upper end thereof and is provided with sealing means thereon below the production iluid outlet for engagement with the wall of the pump chamber. With this construction, the sealing means prevents any sand in the production fluid discharged from the production fluid outlet from packing between the pump unit and the wall of the pump chamber, thereby facilitating removal of the pump unit from the pump chamber. A related object is to provide a production uid outlet Which includes ports above the sealing means at different levels so as to constantly agitate any sand discharged from the production uid outlet with the production fluid.

Another object is to provide a pump which includes a pump unit having a cylinder with a plunger element therein, and which includes means for applying to the exterior of the cylinder a fluid pressure at least equal to the mean between the highest and the lowest fluid pressures applied to the interior of the cylinder. With this construction, radial expansion of the cylinder due to the internal pressure is minimized or prevented to maintain the desired clearance between the plunger element and the cylinder, which is an important feature.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be apparent to those skilled in the art in the light of this disclosure, may be attained with the exemplary embodiments of the invention which are illustrated in the accompanying drawings and which are described in detail hereinafter. Referring to the drawings:

Figs. 1, 2, 3 and 4 are diagrammatic views respectively showing different uid operated pump units of the invention;

Figs. 5, 7, 9, 1l and 13 are diagrammatic views of different fluid operated pumps of the invention each including a pump unit and a valve -unit side-by-side;

Figs. 6, 8, 10, 12 and 14 are diagrammatic views respectively corresponding to Figs. 5, 7, 9, 11 and 13, but illustrating various components of the respective pump and valve units in different positions;

Fig. l5 is a vertical sectional view on a reduced scale showing a fluid operated pumping system of the inven.

6 tion installed in a well, this pumping systent'being a closed system and incorporating a uid operated pump having separate free pump and free valve units;

Figs. 16, 17 and 18 are enlarged, transverse or horizontal sectional views respectively taken along the a1'- rowed lines 16-16, 17-17 and 18-18 of Fig. 15;

Fig. 19 is a longitudinal or vertical sectional view taken along the arrowed line 19--19 of Fig. 16;

Fig. 20 is a downward continuation of Fig. 19;

Fig. 21 is a vertical sectional view taken along the arrowed line 21-21 of Fig. 17 and is a downward continuation of Fig. 20;

Fig. 22 is a downward continuation of Fig. 21;

Fig. 23 is a vertical sectional view taken along the arrowed line 23-23 of Fig. 18 and is a downward continuation of Fig. 22;

Figs. 24, 25, 26, 27, 28 and 29 are transverse sectional views respectively taken along the arrowed lines lli-24, 25-25, 26-26, 27-27, 28-28 and 29-29 of Fig. 2l;

Fig. 30 is an enlarged vertical sectional View of the upper end of a free valve unit of the invention, this valve unit being shown in elevation in Fig. 21;

Fig. 31 is la downward continuation of Fig. 30;

Fig. 32 is a developed view of one component of the valve unit illustrated in Figs. 30 and 31; and

Fig. 33 is -a fragmentary vertical sectional view corresponding to the lower end of Fig. 23, but illustrating an alternative construction.

Fluid operated pump units 41 t0 44 Respectively illustrated in Figs. l, 2, 3 and 4 of the drawings are single acting, fluid operated pump units 41, 42, 43 and 44 of the invention. Each of these pump units includes combined or interconnected engine and pump piston means embodied in a single tubular plunger 46 having an axial production uid passage 43 therethrough, each of the plungers 46 including upper and lower plunger elements 50 and 52 respectively reciprocable in upper and lower cylinders S4 and 56 and interconnected by a hollow rod or tube 58 reciprocable in a bore or cylinder 60 interconnecting the cylinders 54 and 56. Thus, the plunger 46 in each of the pump units 41 to 44 is in effect provided with an intermediate section of reduced diameter. With this construction, upper and lower annular, transverse engine areas 62 and 64 are provided at the lower end of the upper plunger element 50 and the upper end of the lower plunger element 52, respectively, transverse areas 66 and 68 being provided at the upper end of the upper pltmger element and the lower end of the lower plunger element, respectively. The diameter of the upper plunger element 50, designated by the dimensional arrow 70, is slightly less than the diameter of the lower plunger element 52, designated by the dimensional arrow 72. With this construction, the lower engine area 64 is slightly larger than the upper engine area 62, thereby providing each plunger 46 with a small annular, differential engine area which faces upwardly for a purpose to be described. The diameter difference betweeen the plunger elements 50 and 52 may be quite small, e.g., a few thousandths of an inch, and is therefore not readily apparent in the drawings, although it is shown therein.

In each of the pump units 41 to 44, the plunger 46 carries a working valve '74 which opens upwardly to permit upward flow of production uid through the axial passage 48 from an inlet 76 to an outlet 78 in response to downward movement of the plunger, the working valve closing to prevent back flow through the axial passage 48 in response to upward movement of the plunger. Thus, in each of the pump units 41 to 44, the upward stroke of the plunger 46 is the working stroke thereof and the downward stroke of the plunger is the return stroke thereof, in the particular construction illustrated. In each instance, the working valve 74 is a simple ball valve engageable with a valve seat carried by the plunger 46 and encircling the axial passage 4S therethrough. In the pump units 41 and 43, the working valves 74 are at the upper ends of the passages 48, while in the pump units 42 and 44, the working valves 74 thereof are shown as located within the plungers 46.

` he pump units 41 and 43 are provided with standing valves 82 above the corresponding plungers 46 and adjacent the corresponding outlets 78, these standing valves being shown as simple ball valves engageable with valve seats 84. In each of the pump units 42 and 44, a standing valve 86 is provided below the corresponding plunger 46 and adjacent the corresponding inlet 76, the standing valves 36 also being shown as simple ball valves engageable with valve seats 88. Each of the standing valves 82 and 86 opensupwardly in response to upward movement of the corresponding plunger 46, and closes in response to downward movement thereof. t

Considering the manner in which the working and return strokes of the plungers 46 of the pump units 41 to 44 are produced, associated with, and preferably located alongside of each pump unit, is a valve unit comprising an engine valve or engine valve means for controlling the application of pressure to either or both of the engine areas 62 and 64 of each plunger, these valve units being omitted from Figs. l to 4 of the drawings, but being illustrated in detail in subsequent figures of the drawings and being described in detail hereinafter. Also omitted from each of Figs. 1 to 4 for convenience is a source o operating uid at a high pressure and a point of disposal for spent operating uid at a lower pressure, these being illustrated in subsequent iigures and being described in detail hereinafter.

Considering now the pump units 41, 42 and 44, the operating fluid pressure is constantly applied to the upper engine areas 62, the operating huid pressure and the spent operating fluid pressure being applied to the lower engine areas 64 alternately by the associated valve units and to be described. In each of the pump units 41, 42 and 44, the plunger 46 moves upwardly through its working stroke when the spent operating liuid pressure is applied to the lower engine area 64, and moves downwardly through its return stroke when the operating fluid pressure is applied to the lower engine area 64, the return stroke occurring with the operating fluid pressure applied to both the upper and lower engine areas 62 and 64 because of the fact that, as hereinbefore discussed, the lower engine area 64 is slightly larger than the upper engine area 62 to provide a small, annular, upwardly facing, net differential area on which the operating fluid pressure acts to produce the return stroke. This net differential area may be quite small since it is necessary to overcome frictional forces only in producing the return stroke of the plunger of the pump units 41, 42 and 44.

With regard to the pump units 41 and 43, in each of r these the lower engine area 64 of the plunger 46 may also be constantly exposed to the spent operating iiuid pressure, instead of being exposed to the operating fluid pressure and the spent operating iluid pressure alternately. The upper engine area 62 in each of the pump units 41 and 43 is exposed to the spent operating fluid pressure and the operating fluid pressure alternately, instead of being constantly exposed to the operating tluid pressure. Thus, in each pump unit 41 and 43, the working stroke of the plunger 46 is produced when the upper engine area 62 is exposed to the operating Huid pressure, and the return strol-:e is produced when the upper engine area is exposed to the spent operating iiuid pressure. Again, the latter occurs because of the fact that, when the spent operating iluid pressure is applied to both the upper and lower engine area 62 and 64, it acts downwardly on a small, annular, upwardly facing, net differential area resulting from the diameter dierence between the upper andlower plunger elementsSlkand 5,2.l

As in the case of the ptunp units 42 and 44, this net diterential area may be quite small since it is necessary to overcome only friction forces during the return stroke of the plunger 46 of each of the pump units 41 and 43.

It should be noted, however, that since the spent operating huid pressures may be less than the pumped liuid pressure, no net downward force is produced in the pump units 42 and 44 when spent operating iiuid pressure is applied to the areas 62 and 64, and, hence, the units 42 and 44 will operate on the down stroke only when operating pressure is applied to area 64. Bach of the units 41 to 44 may be operated by applying operating pressure constantly to the area 62 and alternately to the area 64, but only the units 41 and 43 may be operated by applying spent operating fluid pressure constantly to the area 64 and alternately to the area 62.

It will be noted that each of the pump units 41 to 44 thus includes an engine or engine means which is actually built right into the pump punger 46, i.e., the engine is concentric with and surrounds an intermediate, reduced-diameter section of the pump plunger'. The working and return strokes of the plunger 46 are effected by constantly applying one of the operating and spent operating iluid pressures to one of the engine areas 62 and 64 and by alternately applying these pressures to the other of the engine areas, the return stroke occurring when 'the same pressure is applied to both engine areas because of the upwardly facing net differential between these areas. The present invention thus provides a cornpact engine and pump piston means combination, which is an important feature of the invention. Also, since the engine areas 62 and 64 are annular areas smaller than the areas 66 and 68, each of the pump units 41 to 44 utilizes a volume of operating uid which is smaller than the volume of production fluid pumped thereby, which is another feature of the invention.

It should also be noted that, in each of the pump units 41 to 44, the production fluid ows from the inlet 76 to the outlet 78 straight through the combined engine and pump piston means by way of the axial passage 48. In other words, since the valve unit for each of the pump units 41 to 44 is located out of axial alignment therewith as hereinafter described, the production fluid flows directly and axially through each pump unit, preferably into a production tubing, not shown in Figs. 1 to 4 of the drawings, connected to the outlet 78 in axial alignment with the pump unit. With this construction, there is no necessity to provide a lateral production liuid bypass around the engine or engine means, or any part thereof, which is an important feature of the invention.

Hereinafter, pump units similar to the pump units 41 to 44 will be considered in connection with valve units incorporating engine valves providing either a three speed action, or a three speed, governing action. Engine valves having a three speed action are disclosed in detail in my prior Patent No. 2,134,174, and engine valves having a three speed, governing action are disclosed in my Patents Nos. 2,311,157, 2,473,864, and 2,580,657. Generally speaking, a three speed engine valve includes a valve member which is moved between two extreme positions at three different speeds in the course of reversing the direction of motion of an engine piston means controlled thereby, while a three speed, governing engine valve governs the motion of the engine and pump piston means when the load on the pump piston means is less than a predetermined value by throttling the admission of operating liuid to, or the exhausting of spent operating 'luid from, the cylinder means in which the engine piston means is disposed, all of this being described in detail in the aforementioned prior patents and being described at least generally hereinafter. As pointed out earlier herein, important objects of the present invention are to provide separate valve units for use with the pump units 41 to 44, or pump units similar thereto, which have actions of the character mentioned.V

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With the foregoing general background in mind, it might be well -to point out -at this juncture that each of the pump units 41 to 44 is preferably controlled by a valve unit incorporating an engine valve having at least a three speed action, although an engine valve providing a governing yaction may also be utilized. Considering the pump unit 4l, if a governing action is applied to this pump, the governing 'action must take place during the working stroke of the plunger 46. If the working stroke is accomplished by constantly applying operating pressure to the area 62, thus the governing is accomplished by throttling the discharge of spent operating fluid from above the lower plunger element 52 to an extent sucient to maintain the pressure `applied to the lower enginearea 64 approximately equal to the operating fluid pressure, until such time `as the load on the plunger 46 attains a predetermined value. Such a governing action applied to the pump unit 41 will keep the plunger 46 from attaining an excessive speed during its working stroke in the event that no load is applied to the area 66 thereof. Such a no-load condition may result from presence of air or gas in the cylinder 54 below the standing valve 82. In the absence of a governing action, the presence of such air or gas would permit the plunger 4.6 to race upwardly until it reaches the upper end of its working stroke, or until it suddenly strikes solid fluid. Similar considerations are applicable to the pump unit 43 except that, in this pump unit, the governing action must occur as the result of throttling the application of the operating uid pressure to the upper engine area 62 during the working stroke of the plunger 46.

In the pump units 42 and 44, governing must occur during the downward or return strokes of the plungers 46 due to the fact that the plungers of these units carry the full production column pressures thereabove. As will be apparent, the reason for this is that the units 42 and 44 are not equipped with standing valves above the plungers 46, but are equipped with the standing valves 86 therebelow. Consequently, the presence of air or gas in the lower cylinders 56 of the pump units 42 and 44 below the plungers 46 thereof could, in the absence of governing, result in downward racing of these plungers until such time as they either reach the ends of their return strokes, or strike solid fluid. If a governing action is utilized in connection with the pump unit 42 or 44, the governing action must occur during the return stroke by throttling the application of the operating fluid pressure to the lower engine area 64 to an extent sufcient to maintain the pressure applied to this area approximately equal to the spent operating fluid pressure.

Fluid operated pump 90 Referring now to Figs. 5 and 6 of the drawings, diagrammatically illustrated therein is a uid operated pump 90 of the invention which included a pump unit 92 and a separate valve unit 94 located side-by-side. The pump unit 92 is identical to the pump unit 41 except that it is provided with the standing valve 86 engageable with the seat SS below the plunger 46, in addition to the standing valve 82 above the plunger. This construction is advantageous, particularly if the valve unit 94 comprises a three speed, non-governing engine valve, which is the case. Similar considerations are applicable to the embodiments of the invention hereinafter disclosed, various ones of such embodiments being illustrated as provided with standing valves 82 and 86 respectively above andk below the plunger 46. The advantage of two standing valves, one above the plunger 46 -and the other therebelow, is that, in the event of pump oif, the resulting high uid velocities are confined to the pump unit itself. With only a single standing valve below the plunger, the entire production column above the plunger would move down with the plunger if no solid iluid were in thespacebetween the plunger and the lower standing valve. By proitl f viding a standing valve above the plunger 46, as well as therebelow, this reverse movement of the production column would be prevented, with the result that only the plunger would move at a high speed. Thus, the use of standing val-ves above and below the plunger 46 is particularly advantageous in the case of a non-governing valve. However, the use of two standing valves is also advantageous in the case of a governing valve since it reduces the load on the piston tending to oause racing of the piston, and thus reduces the amount of governing necessary.

'Ihe pump 90 is shown as having supply, return and production tubings 96, 98 and 100 connected thereto, the supply tubing 96 conveying operating Huid under high pressure downwardly to the pump, the return tubing 98 conveying spent operating iluid at a lower pressure upwardly from the pump to the surface, and the production tubing ltltl being in axial alignment with the pump unit 92 and in communication with the outlet 78 thereof and serving to convey production Huid upwardly from the pump unit to the surface. While the pump 90 is thus shown as incorporated in a closed system wherein the spent operating lluid is returned to the surface independently of the production fluid by way of the return tubing 9S, it will be understood that the invention is in many instances applicable to an open system wherein the spent operating tluid is mixed with the production uid and conveyed to the surface through the production tubing. To convert the system shown from a closed system to lan open system, it is merely necessary to connect the return tubing 98 to the production tubing ltltl above the upper standing valve 32. Similar considerations are also applicable to each of the embodiments herein-after disclosed, each of these embodiments being illustrated as incorporated in a closed system, but being usable in an open system also.

The pump unit 92 and the valve unit 94 are, as hereinbefore mentioned, merely shown diagrammatically in Figs. 5 and 6 of the drawings, and are not specically' shown as removable through tubings of the tubing system 96, 98, 199. However, the pump and valve units 92 and 94, which are shown as axially aligned with the production and supply tubings lltlt and 96, respectively, may be moved between their operating positions in the well and the surface through the production and supply tubings, respectively, important objects of the invention being, as hereinbefore pointed out, to provide a pump having pump and valve units which are movable between their operating positions and the surface either independently of each other, or simultaneously. Such movement of the pump and valve units may be produced hydraulically, or otherwise. Similar considerations are applicable to the embodiments disclosed in Figs, 7 to 14 of the drawings, Figs. l5 to 32 being devoted to an illustrative embodiment wherein all of the structure necessary to attain the foregoing is disclosed in specific detail. Consequently, it will be understood that while the pump and valve units shown in Figs. 5 to 14 of the drawings are not specitically disclosed as movable between their operating positions and the surface through tubings of the associated tubing systems, it is within the scope of the present invention to provide for such movement, utilizing a specilic structure corresponding to that illustrated in Figs. l5 to 32 ofthe drawings.

Considering the pump 90 now in more detail, the valve unit 94 includes a valve member 192 which is reciprocable in a bore 104 in a valve body 106 between two extreme positions, respectively shown in Figs. 5 and 6 of the drawings. The upward, or working, stroke of the plunger 46 occurs when the valve member 102 is in its u-pper position, as shown in Fig. 5, and the return stroke of the plunger occurs when the valve member is in its lower position, as shown in Fig. 6.

The upper engine area 62 of the plunger 46 is always exposed to the operating fluid pressure through a passage 108 which connects the lower end of the cylinder 54 to the supply tubing 96. When the valve member 102 is in its upper position, as shown in Fig, 5, it applies the spent operating fluid pressure to the lower engine area 64 by connecting the upper end of the cylinder 56 to the return tubing 93, as will be described hereinafter. VUnder such conditions, the plunger 46 moves upwardly through its work-ing stroke. Conversely, when the valve member 102 is in its lower position, las shown in Fig. 6, it connects the upper end of the cylinder 56 to the supply tubing 96, which applies operating fluid pressure to the lower engine area 64, thereby producing the return stroke of the plunger 46. Movement of the valve member 102 between its upper and lower positions is controlled by grooves 110 and 112 in the reduced-diameter section of the plunger 46, i.e., in the hollow rod 58 interconnecting the upper and lower plunger elements S and 52. The manner in which the valve member 102 controls the movement of the plunger 46, and the manner in which the plunger in turn controls the movement of the valve member, may best be disclosed by considering the structure and operation of the valve unit 94 more or less concurrently in View of the diagrammatic nature of the showing of the pump 90.

Referring to Fig. 5, when the plunger 46 reaches the upper end of its working stroke, the groove 112 in the reduced section of the plunger interconnects a passage 114 and a control passage 116, the former leading to the return tubing 98 and the latter communicating with a branch passage 110 which leads to the lower end of the valve bore 104. In the branch passage 118 is a check valve 120 which opens in a direction to permit fluid flow out of the lower end of the valve bore `104- only. Consequently, when the groove 112 bridges the passages I114 and 116, the lower end of the valve bore 104 is connected to the return tubing 98 so that fluid can escapefrom beneath the valve member 102 past the check valve 120. When lthis occurs, the valve member 102 starts to move downwardly under the iniluence of the operating uid pressure in the supply tubing 96 constantly applied to the upper end of the valve member. The valve member 102 is a differential-area valve member, including at its upper end a section 122 of reduced diameter reciprocabie in a bore 124 and spaced from the body of the valve member by a stem 126. The lower end of the reduced diameter section 122 and the upper end of the body of the valve member 102 communicate with an annular space 165 around the stem 126, this space being constantly connected to the return tubing 9S by a passage 166.

Under the foregoing conditions, the valve member 102 moves downwardly at the rst of its three speeds, this speed being relatively high since fluid ilow from the lower end of the valve bore 104 to the return tubing 98 by way of the branch passage 118, the passage 116, the groove 112 and the passage 114 relatively unrestricted. As the valve member 102 continues to move downwardly, the lower end thereof eventually covers the end of the branch passage 118 which communicates with the bore 104, such end of the branch passage being located a predetermined distance above the extreme lower end of this bore. tion between the lower end of the valve member 1012 and the return tubing 98 by way of the avenue hereinbefore described is cut oli. At the same time, however, the lower end of an external annular groove 128 in the valve member `102 registers with a passage 130 leading to the return Itubing 9%. Under such conditions, the lower end of the valve member 102 communica-tes with the return tubing 93 through the passage 130, the annular groove 128, a helical groove 132 in the exterior of the valve member, an external annular groove 134 in the valve member, and passages 136 and 138 through When this occurs, comunica-- the valve member, the passage 138 leading to the low er end of the valve member. With these conditions obtaining, the valve member 102 continues to move downwardly, but at a reduced speed, this second speed being controlled by the arca of the helical groove 132, which throttles fluid ilow to provide considerable ilow resistance. The throttling groove 132 may simply be a thread formed on the exterior of the valve member 102.

When the valve member 102 reaches the end of its downward movement at the reduced second speed controiled by the throttling groove 132, an external annular groove in the valve member registers with a passage 142 leading to the return tubing 98. A throttling or metering hole or orice 144 in the valve member 102 connects the annular groove 140 to the passage 136. Under such conditions, the lower end of the valve member 102 is connected to the return tubing 98 through the passage 138, a portion of the passage 136, the throttling hole 144, the annular groove 140 and the passage 142. The resistance offered by the throttling hole 144 determines the third downward speed of the valve member 102, this third downward speed being higher than the second downward speed thereof. Actually, the third speed is determined by the helical groove 132 plus the throttling hole 144, but the latter predominates.

Considering now how the valve member 102 controls the pump unit 92 as the valve member moves downwardly at the three different speeds discussed above the valve member moves downwardly at its first, high speed until such time as V ports or throttling grooves 122:1 in the reduced section 122 thereof begin to uncover a passage 146 leading from the bore 124 to the upper end of the cylinder 56. Thereafter, the valve member 102 moves downwardly at its second, slow speed, under the control of the throttling groove 132, so that the operating fluid pressure from the supply tubing 96 is applied through the passage 146, to the lower engine area 64 of the plunger 46 slowly. Consequently, the plunger -46 is slowly accelerated in the downward direction to initiate its return stroke. As soon as the plunger 46 has been accelerated to some extent in this manner, the annular groove 140 in the valve member 102 registers with the passage 142 to initiate the third speed of downward movement of the valve member. The third speed of the valve member is substantially higher than the second speed thereof so as to fully uncover the passage 146 rapidly after initial downward acceleration of the plunger 46, thereby permitting the plunger 46 to attain its maximum speed with minimum resistance to flow through the passage 146.

The foregoing discussion thus explains the manner in which the plunger 46 initiates downward movement of the valve member 102 and the manner in which the downward movement of the valve member occurs, at three successively different speeds, to reverse the upward movement of the plunger and to produce the return stroke thereof. With the foregoing events completed, the valve member 102 is in its lower position and the plunger 46 is moving downwardly as illustrated in Fig. 6 of the drawings.

When the plunger 46 reaches the lower end of its return stroke, the groove 110 in the reduced section of the plunger connects the lower end of the upper cylinder 54, which is always connected to the supply tubing 96 through the passage 108, to the control passage 116. Communicating with the passage 116 is a branch passage 148, an external annular groove 150 in the valve member 102 registering with this passage when the valve member is in its lower position. The valve member 102 is provided with a passage 152 therein which connects the groove 150 to the passage 138 through a check valve 154. This check valve permits fluid to ow from the passage 152 into the passage 138, but not in the opposite direction. Thus, the lower end of the valve member 102 is placed in communication with the supply tubing 96 through the passage 138, the check valve 154, the passage 152, the annular gioove 150, the branch passage 148, the passage 116, the groove 110 and the passage 108. Consequently, the valve member 102 starts to move upwardly since the operating iuid pressure is applied to an area at the lower end thereof which is larger than the area of the upper end of the reduced section 122 of the valve member. Such upward movement of the valve member 102 is at a relatively high speed, this being the first speed of upward movement of the valve member.

After the valve member 102 has moved upwardly at its first speed a predetermined distance, the annular groove 150 therein moves out of communication with the passage 148 to cut oi communication between the supply tubing 96 and the lower end of the valve member by way of the avenue hereinbefore described. When this occurs, an annular groove 158 in the exterior of the valve member registers with a port 160 which, in turn, communicates with the supply tubing through a passage 162. The annular groove 158 communicates with the annular groove 134 through a helical throttling groove 164 corresponding to the throttling groove 132. Under these conditions, the lower end of the 'valve member 102 is placed in communication with the supply tubing 96 through the passage 138, the passage 136, the annular groove 134, the throttling groove 164, the annular groove 158, the port 160 and the passage 162. The throttling groove 164, which may merely be a helical thread in the exterior of the valve member 102, determines the second speed of upward movement of the valve member, this second speed being relatively low.

The second speed of the valve member 102 in the upward direction begins as V ports or throttling grooves 12211 in the lower end of the reduced section 122 of the valve member start to uncover the passage 146. As this occurs, application of spent operating fluid pressure to the lower engine area 64 of the plunger 46 is initiated through the passage 146, through the annular space 165 around the stem 126 interconnecting the body of the valve member and the reduced section 122 thereof, and through the passage 166 leading from the annular space 165 to the return tubing 98. Thus, as the valve member 102 moves upwardly at its slow second speed, the pressure applied to the lower engine area 64 of the plunger 46 is slowly reduced to the spent operating fluid pressure, whereby the plunger 46 is accelerated upwardly slowly. Thus, the throttling groove 164 controls the upward acceleration of the plunger 46 during the second, slow speed of upward movement of the valve member 102.

As soon as the plunger 46 has been accelerated upwardly somewhat, the valve member 102 begins -its third speed of upward movement, which is higher than its second speed, to uncover the passage 146 rapidly so as to permit the plunger to attain its maximum upward speed. Considering how this is accomplished, when the annular groove 140 in the Valve member 102 registers with a passage 168, communicating with the passage 162, operating uid may ow to the lower end of the Val've member 102 by way of the passage 162, the passage 168, the annular groove 140, the metering or throttling hole 144, a portion of the passage 136 and the passage 138. The metering hole 144 determines the third upward speed of the valve member 102, which is substantially higher than the second upward speed thereof to uncover the passage 146 rapidly once the plunger 46 has received its initial upward acceleration.

Thus, the foregoing describes how the arrival of the plunger 46 at the end of its return stroke initiates upward movement of the valve member 102, and how this upward movement of the valve member continues at three successively diierent speeds to reverse the direction of movement of the plunger 46 so as to produce the working stroke thereof.

It should be noted that the control passage 116 determines the iirst speed of the Valve member 102 in both directions. The direction in which the valve `member 102 moves upon connection of the grooves 11'0and 112' to the control passage 116 is determinedV by the cheekv valves 120 and 154. In other words, when the groove 112 connects the control passage 116 to the return tubing 98, the check valve 120 opens to permit downward move-v ment of the valve member 102. On the other hand, when the groove 110 connects the control passage 116 to the supply tubing 96, the check valve 154 opens to permit upward movement ofthe valve member.

It will be understood that while the fluid operated pump 90 has been described as incorporating the standing valve S6, in the pump unit 92 thereof, this standing valve may be omitted. In other words, the pump unit 41 could be substituted for the pump unit 92, and the operation of such a pump unit -in conjunction with the valve unit 94 would be the same as hereinbefore described.

Fluid operated pump Referring now to Figs. 7 and 8 of the drawings, illustrated therein is a uid operated pump 170 of the invention which includes a pump unit 172 and a separate valve unit 174 disposed in side-by-side relation. The pump unit 172 is identical to the pump unit 42 described previously, except that the standing valve 82, engageable with the valve seat 84, has been added thereto. The valve unit 174 is identical to the valve unit 94.

The important diference between the pump 170 and the pump 90 is that in the pump 170 the working valve 74 is in the lower plunger 52 so the clearance volume of the bottom of the stroke is small. In the pump 90 the working valve 74 is in the upper plunger 50 so the clearance volume is small at the top of the stroke.

Since the valve unit 174 is identical to the valve unit 94 and since the pump unit 172. is very similar to the pump unit 92, the operation of the pump 170 will be apparent from the foregoing description of the operation of the Pump 90.

It will be understood that the upper standing valve 82 may be omitted from the pump unit 172, thereby making this pump unit identical with the pump unit 42. With this substitution, the pump unit and the valve unit 174 would still operate in the same manner as herein* before described in connection with the fluid operated pump 90. Consequently, a further description herein is unnecessary.

Fluid operated pump Illustrated in Figs. 9 and l0 of the drawings is a iiuid operated pump 180 which again includes a pump unit 182 and a valve unit 184 in laterally spaced relation, the pump unit 182 being identical to the pump unit 41, except that it includes the standing valve 86 engageable with the valve seat 88. The valve unit 184 comprises a three speed engine valve which governs during both strokes of the plunger 46. While the double standing valve arrangement illustrated in Figs. 9 and 10 is preferable for the reasons hereinbefore indicated, either the pump unit 41 or the pump unit 42 may be substituted for the pump unit 182.

The valve unit 184 is similar to the valve unit 94, eX- cept that it adds a governing action during both strokes of the three speed action of the valve unit 94. In view of this similarity, identical reference numerals will be utilized in connection with the valve unit 184 insofar as possible and the valve unit 184 will be considered primarily on the basis of the differences between it and the valve unit 94.

The valve member 102 of the valve unit '184, instead of being provided with the reduced section 122, is provided with a longer reduced section 186 connected to the body of the valve member by a relatively short stem 188. The reduced section 186 is provided therein with a relatively wide annular channel 190 which connects theV supply tubing 96 to the passage 146 leading to the lowerengine area 64 of the plunger 46 when the valve memberl 102 is in its upper position, as shown in Fig. 9, and which connects the passage 166 from the return tubing 98 to the passage 146 to apply the spent operating fluid pressure to the lower engine area 64 when the valve member 102 is in its lower position, as shown in Fig. 10. Consequently, the plunger 46 moves downwardly when the valve member 102 is in its upper position, and the plunger moves upwardly through its working stroke when the valve member is in its lower position, this being just the reverse of the interaction between the plunger 46 and the valve member 102 in the fluid operated pump 90. When the plunger 46 reaches the end of its return stroke, the groove 110 therein bridges the passage 114 leading to the return tubing 98 and a passage 192 leading to the hereinbeore described branch passages 118 and 148i. Such bridging of the passages 1114 and 192 initiates downward movement of the valve member 102 by connecting the lower end thereof to the return tubing 98 in the manner hereinbefore described. Referring to Fig. 10, when the plunger 46 reaches the upper end of its working stroke, the groove 112 in the reduced section of the plunger bridges the passage 192 and a passage 194 leading to the supply tubing 96 through a portion of the passage 108. This connects the lower end of the valve member 102 to the supply tubing 96 through the passage 108, the passage 194, the groove 112, the passage 192, the branch passage 148, the groove 150, the passage 152, the check valve 154 and the passage 138, thereby initiating upward movement of the valve member 102 in much the same manner as hereinbefore described in connection with the valve unit 94.

Thus, it will be apparent that the tirst speeds of the valve member 102 are the same as for the non-governing valve unit 94, except that they occur in response to movement of the plunger 46 in reversed directions. The second speeds of the valve member 102 of the valve unit 184 are also the same as for the valve unit 94, except for the reversed directions of movement of the plunger 46. The desired governing action during both strokes is` accomplished by the third speed control of the valve member 102, as will now be described.

Considering Fig. 9 of the drawings, the passage 146 is provided with an extension 198 which communicates with ports 200 and 202 leading to the valve bore 104. Considering upward movement of the valve member 102, as the valve member moves upwardly at its second speed, the upper edge of the groove 140 starts toregister with the port 200, thereby connecting the lower end of the valve member 102 to the cylinder 56 above the lower plunger element 52. by way of the passage extension 198, the port 200, the groove 140, the passage 136 and the passage 138, Under these conditions, the lower end of the valve member 102 is also connected to the supply tubing 96 through the passage 162, the port 160, the throttling groove 164, the annular groove 134, the passage 136 and the passage 13S.

The reduced section 186 of the valve 102 has V ports or throttling grooves 1220i and 12.2b which throttle the fluid at the start of the stroke. The slow motion of the valve starts when the small ends of the V ports are in line with the leading edge of the annular channel 190 and the annular passage 165. The third speed in the governing valve starts when the governing line A--A and the governing line B-B are in line with the leading edges of the annular passages 190 and 16S, respectively. At this point the areas of the V ports determine the maximum speed or governing speed of the piston 46, which may be varied by varying the V ports to shift the governing lines A-A and B-B vertically. The passages 200 and 202 are located so that the leading edges of these passages will line up with the annular grooves 128 and 140, respectively, when the lines A-A and B-B are in line with annular passages 190 and 165 respectively. Therefore, if there is no load on the plunger 46 in either direction of movement, there will be a large pressure 1&1 drop across the V ports and hence the pressure in the passages 146, 19S, 200 and 202 will differ from the pressure on the other side of the valve 186.

Assuming that the area of the upper end of the reduced section 186 of the valve member 102 is one-half the area of the lower end of the valve member, if the pressure drop mentioned in the preceding sentence is equal to one-half of the difference between the operating uid pressure in the supply tubing 96 and the spent operating fluid pressure in the return tubing 93, then the pressure applied to the lower end of the valve member is this mean pressure. Consequently, the axial forces applied to the valve member are balanced and the valve member cannot move upwardly past the position under consideration. However, as soon as the plunger 46 encounters solid iluid so that some load is applied thereto, the speed of the plunger will decrease so that the pressure drop acrosss the V ports will decrease a corresponding amount. Such a decrease in this pressure drop results in an increase in the pressure applied to the lower end of the valve member 102 to cause the valve member to resume its upward movement. Eventually, the valve member 102 moves upwardly sufciently to permit the channel 190` in the reduced section 186 thereof to provide normal communication between the supply tubing 96 and the lower engine area 64 by way of the passage 146. Thus, during the downward stroke of the plunger 46, the valve member 102 governs by throttling the application of operating uid pressure Vfrom the supply tubing 96 to the lower enginee area 64 until such time as the load on the plunger 46 attains a predetermined value.

Considering the `governing action during the working stroke of the plunger 46, when the plunger reaches the end of its return stroke prior to beginning its working stroke, the groove in the reduced section of the plunger bridges the passages 114 and 192 to connect the lower end of the Valve member 102 to the return tubing 9S through the passage 114, the groove 110, the passage 192, and the passage 11S. Thus, the valve member 102 starts moving downwardly at its rst speed, and subsequently moves downwardly at its second, slow speed, all as hereinbefore described. As in the case of governing during the return stroke of the plunger 46, governing during the working stroke thereof is accomplished through the third speed control for the valve member 102. The third speed of downward movement of the valve member 102 as the plunger 46 begins its working stroke normally results from registering of the annular groove with the port 202, which places the metering hole or orifice 144 in communication with the passage exten sion 198 leading to the lower engine area 64. Under such conditions, the plunger 46, in moving upwardly, must discharge iluid into the return tubing 98 through the passage 146, the V ports 12219, the annular groove and the port 166. If there is no load on the plunger 46 during its working stroke, a large pressure drop across the throttling ports 1221) will exist and, therefore, the pressure applied to the lower engine area 64 will be higher than the spent operating iiuid pressure in the return tubing 98. The same pressure is also applied to the lower end of the valve member 102 through the passages 198 and 202 and the throttle hole 144, and, if this. pressure is equal to the mean between the operating fluid pressure in the supply tubing 96 and the spent operating lluid pressure in the return tubing 98, the forces applied to the valve member are balanced and the valve member will not move downwardly. Consequently, the plunger 46 will move upwardly at a reduced speed, controlled by the throttling ports 122i), until it hits solid iluid in the cylinder 54 above the plunger element S0. As this occurs, the pressure drop through the throttling ports 1221; will decrease, which will lower the pressure applied to the lower end of the valve member 102 to a value less than the mean between the operating iluid pressure `and the spent operating iiuid pressure. This will enable the valve member 102 to continue its downward movement at its third speed. Thus, governing during the working stroke of the plunger 46 is provided by throttling the discharge of uid from above the lower engine area 64 to the return tubing 98, the pressure applied to the lower engine area being maintained substantially equal to the operating uid pressure until such time as the plunger strikes solid uid after having compressed any air or gas present in the cylinder 54 above the plunger element 50.

4If the pump unit 182 is lled with solid fluid, the pressure drop across the throttling ports 122a will be low as the valve member 102 moves upwardly and, therefore, the pressure in the passage extension 198 will approach the operating fluid pressure as the valve member 102 moves upwardly into its upper position. Similarly, the `pressure drop across the throttling ports 122b will be low as the valve member 102 moves downwardly into its lower position and, therefore, the pressure in the passage extension 198 will approach the spent operating uid pressure. Under such conditions, the third speeds of the valve member 102 would be the same as they would be without governing. Thus, governing occurs only when the load on the plunger 46 is less than a predetermined value.

Although the valve unit 184 has been described as governing during both strokes of the plunger 46, it should be pointed out that governing during the upward or working stroke is desirable only if the pump valve arrangement incorporated in the pump unit 41 is used, and governing on the downward stroke is desirable only if the pump valve arrangement of the pump unit 42 is used, or if the pump valve arrangement of the pump unit 182 is used, i.e., if the two standing valves 82 and 86 are used. There is no necessity for governing during the downward stroke of the plunger 46 except when the lower standing valve 86 is used without an upper sta-nding valve 82, as in the case of the pump unit 42. -If the lower standing valve 86 is omitted, governing during the upward or working stroke only can be obtained by connecting the port 202 to the return tubing 98, instead of to the passage extension 198. Thus, with this simple change, which is illustrated in Figs. 11 and l2 of the drawings, the valve unit `184 can be made to govern during the upward stroke of the plunger 46 only.

Fluid operated pump 210 Figs. ll and l2 of the drawings illustrate a iluid operated pump 210 of the invention which again includes a pump unit 212 and a valve unit 214 in side-by-side relation. The pump unit 212 is identical to the pump unit 43, except that it additionally includes the standing valve 86 engageable with the valve seat 88. The valve unit 214 includes a valve member 102 which is identical to the valve member of the valve unit 184, the only differences between the valve unit 214 and the valve unit 184 residing in the porting external to the valve member. 'For the sake of uniformity, identical reference numerals will be applied to the valve unit 214 insofar as possible.

As hereinbefore discussed in connection with the pump unit 43, the spent operating uid pressure is constantly applied to the lower engine area 64 of the plunger 46 of the pump unit 212, this being accomplished through a passage 216 interconnecting the upper end of the cylinder 56 and the return tubing 98. The operating lluid pressure and the spent operating fluid pressure `are alternately applied to the upper engine area 62 through the passage 108 under the control of the valve member 102 to produce the upward and downward strokes of the plunger, respectively. As shown in Fig. ll, when the valve member 102 is in its upper position, the annular channel 190 in the reduced section 186 of the valve member connects the passage 108 to the supply tubing 96 to produce the upward or working stroke of the plunger 46. Conversely, when the valve member 102 is in its lower position, as shown in Fig. l2, the annular channel 190 connects the passage 108 to the passage 166 leading to the return tubing 98. Under such conditions, the spent operating iluid pressure is applied to the upper engine area 62 so that the spent operating fluid pressure acting on the dilerence between the upper and lower engine areas 62 and 64 produces the downward, or return, stroke of the plunger 46, as hereinbefore described. The manner in which the valve member 102 is displaced between its upper and lower positions to accomplish the foregoing will now be considered,`the valve member providing a governing action during the upward stroke of the plunger 46 only,

Referring to Fig. l2 of the drawings, as the plunger 46 reaches the end of its return stroke, the groove 110 in the hollow rod 58 bridges passages 218 and 220, the former communicating with the supply tubing 96 and the latter communicating with the branch passages `118 and 148. Thus, operating fluid pressure from the supply tubing 96 is applied to the lower end of the valve member 102 through the passage 218, the groove 110, the passage 220, the branch passage 148, the annular groove 150, the passage 152, the check valve 154 and the passage 138, thereby moving the valve member upwardly at its first upward speed. The second upward speed of the valve member 102 begins when the annular groove moves out of register with the branch passage 148. At this time, the groove 158 in the valve member registers with the port -160 communicating with the supply tubing 96 through the passage 162. Under these conditions, operating fluid from the supply tubing 96 is delivered to the lower end of the valve member 102 through the passage 162, the port 160, the annular groove 158, the throttling groove 164, the annular groove 134, the passage 136 and the passage 138. Thus, the resistance olered by the throttling groove 164 deter.- mines the slow second speed of the valve member.

Considering the governing action during the upward stroke of the plunger 46, as the valve member 102 moves upwardly, the annular groove 140 therein begins to register with the port 200, this port being connected, by a passage 222, to the passage 108 controlled by the annular channel and leading to the upper engine area 62. If there is no load on the plunger 46 when the annular lgroove 140 begins to register with the port 200, the pressure in this port will be low, due to the pressure drop in the V ports 122a, which are in a position such that the line A-A is in register with the upper edge of the valve body =at 122e, so that a large pressure drop will exist across the throttling ports 122a in response to llow of operating uid from the supply tubing 96 through the passage 108 into the cylinder 54 below the upper piston 50. Since the lower end of the valve member 102 is exposed to the low pressure in the port 108 through the passage 222, the port 200, the annular groove 140, the hole 144, the passage 136 and the passage 138, the valve member 102 will not move upwardly as long as the pressure applied to the lower end thereof is equal to the mean between the operating uid pressure and the spent operating uid pressure, again assuming that the area ofV the upper end of the reduced section 186 is equal to one-half of the area of the lower end of the valve member 102. When the plunger 46 hits solid fluid, the aforementioned pressure drop through the throttling ports 122a will decrease, thereby increasing the pressure applied to the lower end of the valve member to cause it to resume its upwardmovement. This upward movement of the valve member 102 takes place at the third speed, which is determined by the metering hole 144,`to`connect'the upper engine area 62 to the supply tubing 96 rapidly so as to enable the plunger 46 to attain its normal upward speed. Thus, the governing action during the upward stroke yof the plunger 46 takes 

